1. Field of the Invention
The present invention generally relates to the attenuation of signals and, more particularly, to a precision digitally-controlled variable attenuation circuit for adjusting the attenuation of a signal in an external circuit, such as in an automatic gain control (AGC) loop.
2. Description of the Prior Art
Certain military applications, such as equipment for testing circuits in missiles under development by the Department of the Navy, require precise automatic gain control (AGC) loops. The AGC loops in this test equipment utilizes variable attenuation circuits. Up to the present time, variable attenuation circuits available on the commercial market have been used for this application.
However, these commercial variable attenuation circuits are totally analog and not very precise and thus do not achieve the precision attenuation needed in the AGC loops for this application. Thus, a need exists for a variable attenuation circuit capable of providing more precision.